CheapSolver - General Purpose Equation Solver

Version 1.0 - April, 1989

Leander Software & Consulting
15072 E. Mississippi Ave
Box # 51
Aurora, CO 80012

Copyright (c) 1989 - Leander Software & Consulting

INTRODUCTION

CheapSolver is a shareware program which will solve mathematic
equations and was written to help high school and college
students survive their math classes. While taking Calculus and
helping my wife with Algebra, I started looking for programs
which would allow us to check our homework and ease the drudgery.
The commercial programs were far too expensive and complex for
our needs and, at the time, there was nothing in the shareware
catalogues that would help either. Being the ambitious fool that
I am, I decided to write one myself. The result is CheapSolver.

OPERATION

CheapSolver will solve an algebraic equation with one unknown
variable using numeric methods. The formula can contain up to 20
variables and can use any of sixteen predefined math and trig
functions. After entering the equation, the program will issue a
prompt for each variable specified, enter either a numeric value
or a question mark (?) to specify the unknown variable. The
program will next request the range in which to search for
solutions, then after a short wait will list the solutions found
(up to 20). At this point, you may print the results, start over
or exit the program.

To start the program, enter

A>chsolv

Equations are entered in a form similar to the BASIC language.
Variables can be up to four characters long and must start with
a letter (A..Z), followed by letters or numbers and are converted
to upper case before the formula is evaluated.

Arithmetic operands are:

- subtract
* multiply
/ divide
^ exponentiation

The following math and trig functions may also be included:

Arithmetic Functions
ABS (x) - Absolute Value
INT (x) - Integer portion of argument
SGN (x) - Sign of argument (returns -1, 0 or +1)
SQR (x) - Square Root

Logarithmic Functions
EXP (x) - Exponent of e ( e ^ x )
LNE (x) - Natural Logarithm (base e)
LOG (x) - Common Logarithm (base 10)

Trigonometric Functions (all trig functions based on radians)
ACS (x) - ArcCosine
ASN (x) - ArcSine
ATN (x) - ArcTangent
CSC (x) - Cosecant
COS (x) - Cosine
COT (x) - Cotangent
SEC (x) - Secant
SIN (x) - Sine
TAN (x) - Tangent

Parenthesis () and spaces may also be included as needed. The
formula is evaluated from left to right using the standard order
of precedence (exponentiation, multiplication/division,

Examples of valid equations:

2*x-3 = 5
y = pi/2 + cos (3*x)
x^2 - 2*x + 4 = 0

Once the equation is interpreted, prompts will be issued for each
variable found. Enter a numeric value for each known variable
and a question mark (?) for one the unknown variable. Up to 20
variables can be used but only one variable can be unknown.
Numbers can be values from -10^38 to +10^38; make sure that any
computations do not exceed this range or the program will
terminate.

A prompt will be issued requesting the minimum and maximum values
that can be used for the result. Since many equations (such as
trig functions) can produce an infinite number of results, this
range limits the number of values found. The first 20 results
will be printed.

To exit the program, select 'Q' (quit) after the results are
printed or press enter when the program prompts for the next
equation. To use the same equation several times, enter 'same'
when the equation is requested.

REGISTRATION

This program is distributed using the "shareware" concept. You
may copy it and distribute it to others for use on a trial basis
as long as the program file (CHSOLV.EXE), this documentation and
the registration form are included without any modifications. It
may also be put on bulletin boards and distributed through any of
the shareware catalogues.

If you find this program useful, you are encouraged to become a
registered user. For the \$20.00 registration fee, you will
of the program. To print the registration form use the following
DOS command:

a> type chorder.frm >prn

PROGRAM PROBLEMS

If you discover a formula that cannot be solved by this program
(within the realm of real numbers {-10^38 to < 10^38}) please
print the results and send them to the address listed on the
registration form with an explanation of what the correct answer
is. We want to know of problems even if you are not a registered
user.

LEGAL STUFF

Use of this software signifies your agreement that Leander
Software & Consulting grants you a licence to use the CheapSolver
program "as is" with no guarantees. The program may also be
copied and distributed according to the restrictions stated
above. We will not be liable for any damages or loss of income
caused from using the program and cannot guarantee the accuracy
of any program results.

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